Effect of aging on F-111 flare and stall question

[dterrick 0]

When I was a "little" kid I used to take things apart to see how they worked. I can't do this with the atmosphere and I won't do it with my canopy, a well-used Raven.

I'm trying to determine, in "correct" aerodynamic terms, what happens that makes old F-111 so quirky. By this I mean

1) VERY steep glide in anything more than about 10 mph winds (loaed at 0.95:1)

2) Very little change in attitude during a flare in light winds making timing and control difficult to perfect (yes, I've flown ZP and I don't get any of that "lifting" sensation with the Raven)

3) Because of #2 I've been going deeper and faster into brakes to "compensate" and think I am finding the stall point. Ugly landings are almost always a forward fall into the peas, but none have been bad enough to even scratch my altimeter. Despite this, my patience with non-tiptoe landings is waning.


___________________________


Our season is over in a few weeks (damn winter!) and I'm faced with the issue of this less-than-hospitable main canopy. I swore I wouldn't downsize until I could land this one "backwards and blindfolded" but I'm beginning to think this goal is too lofty for what the canopy has left.

Anyone else been there and found the cure?

Can anyone tell me in aerodynamic terms how to "correctly" compensate, or must I simply be "perfect everytime"?

the Dave

Life is very short and there's no time for fussing and fighting my friend (Lennon/McCartney)

[SkymonkeyONE 3]

Your canopy is played out. A decent rigging loft can test the porosity of your fabric, but my guess is that thing is leaking air like a seive. While it may be large enough that you think it ought to let you down easy, if it's worn out, that just won't be the case.

Chuck

[dterrick 0]

..it's THAT easy to answer? Daammm, I was hoping for something like a Voodoo curse (not the container, but I want one of those, too!) to cure me of my ills. The one thing that has made me wonder about the worn-outedness of this Raven is that it STILL opens briskly - in fact it's had master rigger mods and a diet of trash packing in effort to tame it with acceptable success. Sounds like I have a cool car cover right now though .

So, if indeed this canopy is fried, how much leeway can/should I give myself when I order new? I nailed the landing the first time I flew a Sabre 190 (loaded 1.08:1) but that was 50 jumps or so ago. Given I have 112 jumps (and have fought this Raven since jump #25) and good accuracy skills (landings notwithstanding ) is stepping into a brand new Hornet 170 (for eg) too much? I like to fly it hard and land it conservatively -

Dave

PS: my master rigger suggested "don't bother spending the $ on a porosity test, most F-111 0-3 reads 3+ after a couple hundred jumps. Maybe THIS is why the thing packs so damn easily!!

Life is very short and there's no time for fussing and fighting my friend (Lennon/McCartney)

[RichM 0]

I calculate that at 1.2:1 under the Hornet 170, which sounds fairly reasonable. But get the recommendations from instructors at your dz who see you fly, and if they ok it, try to demo one first, and demo lots of other canopies while you're there too.

Rich M

[bobsoutar 0]

Your rigger is right. Bin it and get yourself on something else. A 170 sounds about the right size to go for and there are plenty of good canopies out there at that size - demo a few betofe you decide and check that it will go into your bag/container ok as zp packs up bigger than your f111.

[councilman24 36]

The fabric may actually be more than 3 cfm in just a few jumps AND pack jobs. Just packing a F-111 type fabric canopy increases the porosity. One of the reasons this effects the canopy so much is that the air leaking through the material disrupts the airflow over the airfoil of the canopy, decreasing lift.

No F-111 type main is worth having the porosity tested. Time for something new!

I'm old for my age.
Terry Urban
D-8631
FAA DPRE